Ants point to clues about climate change
New research from NASA
indicates that photons move
like ants, except photons are
smaller and less crunchy.
A team led by Yongxiang
Hu of NASA’s Langley Research Center
found a correlation between how long it
takes for an ant to enter and exit a colony
and how long it takes a photon to enter
and exit snow. The team’s findings point
toward a simpler method for measuring
snow depth that, in turn, has bearings on
studying climate, weather, and Earth’s
water cycle.
Hu borrowed a chapter from mathematics
and biology research that observed
that the average time an ant spends
wandering around inside a colony before
emerging corresponds to ~4× the volume
of the colony divided by its surface area.
Courtesy of iStock.com/atakan.
Naturally, this led Hu to think about
clouds, photons, and snow. “I studied
properties of clouds and learned light
bounces among cloud particles randomly,
similar to the ants’ movement inside its
colony,” he said. “So, I thought that
the ants theory might apply to snow,
too, since snow comes from clouds.”
Hu and his team developed a model
simulation to verify that the math translated
from ant behavior to that of photons.
They found that it was possible to use
a similar equation to measure both. In
the same way that an ant goes inside the
colony and moves about randomly before
coming back out, a photon of light from a
lidar instrument enters snow and is scattered
randomly within the snow particles
before it exits.
By applying the model simulation to
lidar measurements taken by NASA’s
ICESat-2 satellite, the researchers
measured the average distance a
photon traveled in snow. The
simulation showed that snow depth
was approximately half the average
distance that the photon traveled inside
the snow.
The technique will enable future
researchers to measure the depth of layers
of snow covering sea ice surfaces and
mountains to gain a clearer picture of
how the climate crisis is affecting sea
ice thickness, as well as the thickness of
glaciers over land.
Snowpack provides significant water
resources in many regions of the world,
making it important for water resource
management. Compared to forecasting
snowfall, forecasting rainfall is relatively
easy. Climate models consistently predict
an increase in global rainfall of anywhere
between 3% and 7%. But estimating how
snowfalls may decline in midlatitude
regions as a result of global warming
is much more complex. This is
where Hu’s technique could make
a difference.
“I am confident this technique will
revolutionize how we forecast snow
evolution in the future and model sea
ice changes, and we are already
working on the design of the next
generation of satellites specifically for
snow depth,” he said.
Who knew that spying on the personal
habits of ants could produce insights
about global precipitation?
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